Yakov,
Position sizing for secondary entries is very important for psychological reasons and I do it all the time.
If the first position is a losing position, then you would not stress as quickly as if you had a full losing position.
Taking a second position at a better entry price gives you a psychological flexibility... But also the satisfaction that you are on average winning compared to the Robot's position.
However, in terms of total return, it is better to be invested 100% at the first signal. This is what has been back-tested. But, please understand that the robot does not care about the traditional psychological issues that every trader faces at one point or another. It trades probabilities and there is a clear declining average position earnings from the initial triggering date.
Pascal